As a sealing member using a resin composition, for example, a U seal and a seal ring formed by cutting processing of fluororesin such as polytetrafluoroethylene and the like (patent document 1), a seal ring formed by injection molding of a polyetheretherketone resin and an amorphous carbon powder as main constituent components (patent document 2), a TIP seal formed from a sliding composition composed of a liquid crystal polymer, fluororesin, and a carbon fiber having a tensile elastic modulus of not more than 10000 kgf/mm2 (patent document 3) and the like have been proposed. Furthermore, it is known that a TIP seal formed from polyphenylene sulfide or polyimide, or a synthetic resin comprising liquid crystal polymer as a substrate is used in a scroll compressor (patent document 4).
As a TIP seal mounted on an apparatus generally without diameter extension or diameter reduction, those described in the above-mentioned patent document 1, and seals produced by injection molding thermoplastic resins such as polyphenylene sulfide and polyetheretherketone are expanding in the market. However, since polyphenylene sulfide, polyetheretherketone and the like are rigid, they problematically cannot be applied to a resin sealing member to be mounted after diameter expansion or diameter reduction such as a square ring and a U seal.
On the other hand, since fluororesins such as polytetrafluoroethylene and the like have high molten viscosity, they are difficult to process by molten processing such as injection molding and the like, and generally require preforming, calcination, and cutting processing by a machine such as lathe, milling machine and the like, which is disadvantageous in terms of production speed, namely, mass-productiveness, and production cost.
In addition, a seal ring using polyetheretherketone is considered to have a problem of high leakage amount. One of the causes thereof is considered to be high rigidity of polyetheretherketone. That is, a seal ring using a rigid resin material does not allow easy deformation in response to the pressure applied during operation of a tight sealing apparatus and shows low adhesion to a seal groove and the like of a tight sealing apparatus, which is considered to cause a high leakage amount.